Contrary to myths perpetuated by the mass media, studies show that most stalkers are men, have high IQ's, advanced degrees, and are middle aged (Meloy and Gothard, 1995; and Morrison, 2001).
Rejected stalkers are intrusive and inordinately persistent. They recognize no boundaries â personal or legal. They honor to "contracts" and they pursue their target for years. They interpret rejection as a sign of the victim's continued interest and obsession with them. They are, therefore, impossible to get rid of. Many of them are narcissists and, thus, lack empathy, feel omnipotent and immune to the consequences of their actions.
(From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase the print book, or 16 e-books, or 2 DVDs with 12 hours of video lectures on narcissists, psychopaths, and abuse in relationships: http://www.narcissistic-abuse.com/thebook.html)